TUCSON, Ariz.—The cactus ferruginous pygmy owl population in northern Sonora, Mexico, has declined over the past nine years, according to an ongoing monitoring effort by University of Arizona researcher Aaron Flesch. The report’s dismal findings support efforts by the Center for Biological Diversity and other conservation organizations to reinstate protection for the tiny owl under the Endangered Species Act.

“The pygmy owl is near extinction in Arizona, has declined markedly in northern Mexico, and needs immediate protection,” said Noah Greenwald, science director at the Center for Biological Diversity .

On May 30, the U.S. Fish and Wildlife Service determined that a petition from the Center, Defenders of Wildlife, and Public Employees for Environmental Responsibility presented substantial information that pygmy owls in Arizona and Sonora may warrant protection as an endangered species. The agency is currently conducting a review of the species’ status. The pygmy owl was listed as an endangered species in Arizona until 2006, but was removed by the Bush administration based on the bird’s presence in Mexico.

“The pygmy owl should never have been removed from the endangered species list,” said Greenwald. “It desperately needs the protection of the Endangered Species Act to survive.”

The study found that pygmy owls in northern Sonora have declined 4.4 percent per year, or 36 percent overall since the year 2000, and concluded that “should this apparent decline continue, recovery strategies that rely on pygmy-owls from northern Sonora and persistence of pygmy-owls in the Sonoran Desert could be jeopardized.” In 2008, pygmy-owl abundance and territory occupancy were the lowest since the study began.

“The combination of habitat destruction and climate change may be the nail in the coffin for the cactus ferruginous pygmy owl in the Sonoran Desert,” said Greenwald.

Declines of pygmy owls were more severe in regions of northern Sonora with greater intensity of human land use, such as woodcutting and agricultural development. Evidence also suggests that reproductive success was lower during years with low winter rainfall. Given recent findings by the National Research Council that drought in the Southwest may become more common due to global warming, this raises a red flag.

The Center for Biological Diversity is a nonprofit conservation organization with more than 180,000 members and online activists dedicated to the protection of endangered species and wild places.